package notwork;

import java.io.IOException;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.SocketException;

public class UdpEchoServer {
    private DatagramSocket socket=null;

    public UdpEchoServer(int port) throws SocketException {
        socket=new DatagramSocket(port);
    }

    public void start() throws IOException {
        System.out.println("启动服务器");

        while(true){
            DatagramPacket requestPacket=new DatagramPacket(new byte[4096],4096);
            socket.receive(requestPacket);
            String request=new String(requestPacket.getData(),0,requestPacket.getLength());
            String response=process(request);
DatagramPacket responsePacket=new DatagramPacket(response.getBytes(),response.getBytes().length,
        requestPacket.getSocketAddress());
socket.send(responsePacket);

            System.out.printf("[%s:%d] req:%s,resp: %s\n",requestPacket.getAddress().toString(),
                    requestPacket.getPort(),request,response);
        }
    }

    private String process(String request){
        return request;
    }

    public static void main(String[] args) throws IOException {
        UdpEchoServer server=new UdpEchoServer(9090);
        server.start();
    }
}
